The invention relates to a high temperature filter, including a diesel engine exhaust filter, and to a method for making same.
As regulatory agencies continue to mandate reduction of particulate emissions from diesel engines, there has been increased activity in the development of exhaust gas filters for diesel engines. A typical exhaust filter will trap the particulate material contained in the exhaust stream, and to prevent clogging filter and the resultant increase of load on the engine due to increased back pressure, the particulate material is burned or incinerated from the filter, i.e. the filter is regenerated. A diesel engine exhaust filter must have high temperature resistance and durability, and it has been proposed to use ceramic materials as the filter media, for example U.S. Pat. Nos. 4,017,347, 4,652,286, 5,322,537, 6,444,006, incorporated herein by reference.
The present invention arose during continuing development efforts directed toward high temperature filters, including for diesel exhaust. In a particularly desirable aspect, the invention enables shaping and forming of the filter while in a malleable green pre-form state, prior to rigidization. In another desirable aspect, the filter provides lower back pressure, for improved performance.